Cut-off gate for mold

ABSTRACT

A cut-off gate for a mold to prevent plastic material from oozing out of the mold opening after the nozzle has been removed. The mold is provided with a semi-spherical seat in communication with the mold cavity through an opening in the seat, a cut-off gate of substantially semi-spherical configuration having an outer semi-spherical surface adapted to engage the semi-spherical surface of the seat and also having an opening so that, in a closed position of the gate the two openings are out of registry with each other; in the open position, the openings in the gate and the seat are in registry with each other and with an opening in a supply nozzle. Means are provided for rotatably mounting the gate with respect to the semi-spherical seat, with further means responsive to the movement of the supply nozzle towards and away from the mold for rotating the gate into the open and closed positions,respectively.

United States. Patent [191 Asner [451 July 3,1973

[ CUT-OFF GATE FOR MOLD [75] Inventor: Jerome L. Asner, Oklahoma City.

Okla.

3/1972 Schwartz 425/245 X Primary Examiner-J. Spencer Overholser Assistant ExaminerRichard Bernard Lazarus Attorney-William S. Dorman ABSTRACT A cut-off gate for a mold to prevent plastic material from oozing out of the mold opening after the nozzle has been removed. The mold is provided with a semispherical seat in communication with the mold cavity through an opening in the seat, a cut-off gate of substantially semi-spherical configuration having an outer semi-spherical surface adapted to engage the semispherical surface of the seat and also having an opening so that, in a closed position of the gate the two openings are out of registry with each other; in the open position, the openings in the gate and the seat are in registry with each other and with an opening in a supply nozzle. Means are provided for rotatably mounting the gate with respect to the semi-spherical seat, with further means responsive to the movement of the supply nozzle towards and away from the mold for rotating the gate into the open and closed positions,respectively.

5 Claims, 3 Drawing Figures CUT-OFF GATE FOR MOLD FIELD OF THE INVENTION The present invention relates to a cut-off gate for a mold and more particularly one which can be operated automatically by the approach and withdrawal of the supply nozzle.

PRIOR ART BRIEF SUMMARY OF THE INVENTION The present invention involves a mold wherein a semi-spherical seat is in registry with the mold cavity through a circular opening in the seat. A semi-spherical cut-off gate is rotatably mounted in the spherical seat. The gate has an opening therein of substantially the same size as the opening in the seat, and the gate is rotatable from a closed position where the holes are out of registry with each other to an open position where the two holes are not only in registry with each other but with the opening in a supply nozzle. The semispherical gate is attached to a pair of rods which extend transversely outwardly from the gate perpendicular to the path of movement of the nozzle. These rods are suitably journalled so that the gate is rotatable as aforesaid. The inner surface of the gate is shaped in a semispherical manner so as to correspond with the outer semi-spherical surface of the supply nozzle. One of the rods which rotatably supports the gate is provided with an outwardly projecting arm and a spring means extends from this arm to a spring retainer means which is attached to the outside of the mold. The effect of the spring is to urge the gate into a closed position. However, the nozzle is provided with a flange or other arm engaging means whereby, as the nozzle approaches the mold and the semi-spherical surface of the nozzle engages the inner semi-spherical surface of the gate, this arm engaging means mounted on the nozzle will urge the arm against the action of the spring to rotate the gate into the open position where the hole in the gate and the hole in the seat are in registry with each other and with the opening in the supply nozzle. Conversely, as the nozzle is withdrawn from the mold, the spring immediately rotates the cut-off gate to the closed position thereby preventing any of the foam-type plastic material from expanding outwardly through the mold opening.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING FIG. 1 is a view, partly in section, showing the relative positions of the mold, gate and supply nozzle when the gate is in the closed position.

FIG. 2 is a view similar to FIG. 1 showing the relative positions of the members where the gate is in the open position.

FIG. 3 is a plan view of the cut-off gate per se.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings in detail, FIGS. 1 and 2 show a mold 10 having a mold cavity 12 therein. An element l4 referred to herein as a gate receiving means is mounted so as to be in registry with the mold cavity 12 through the seat and opening later to be described. The gate receiving means 14 has a semi-spherical seat 16 and an opening 18 at the bottom of the seat providing communication with the mold cavity 12.

A semi-spherical cut-off gate 20 (actually the gate is somewhat less than a semi-sphere) is mounted such that its outer spherical surface 22 conforms with and registers with the semi-spherical surface 16 of the seat. The gate 20 is also provided with an inner semispherical surface 24 which is adapted to register with the semi-spherical surface of the nozzle later to be described. The gate also has a circular opening 26 which is adapted to register with the opening 18 when the gate is in the open position shown in FIG. 2. As shown in FIG. 3, a gate 20 is connected at its opposite ends to a pair of rods 28 and 30 which provide an axis of rotation for the gate. The gate receiving member 14 is provided with a pair of slots or openings (not shown) located on opposite side edges of the member 14 providing journals for the rods 28 and 30. A cover plate 32 is mounted on the top of the gate receiving member 14 and has portions (not shown) covering the slots referred to above to hold the rods 28 and 30 in their journals. The cover plate 32 is provided with a central opening 34 substantially equal to the diameter of the nozzle which will be described later.

The plate 32 has attached thereto an extension 36 from which upwardly projects a spring retainer 38. The rod 30 has an arm 40 extending radially outwardly and terminating in a horizontal portion 42. A spring 44 is mounted between the spring retainer 38 and the horizontal portion of the arm 40 such that one end of the spring 44 is curved at 46 to be received in a reduced portion 48 of the spring retainer 38, whereas the other end 50 of the spring 44 is bent at right angles so as to received in a hole 52 in the horizontal portion 42 of the arm 40.

The nozzle 54 is essentially conventional and connects with a supply of molten plastic material (not shown), preferably of the foaming type. The end of the nozzle 54 is provided with a spherical surface 56 which terminates in an opening 58. In the position shown in FIG. 2, the opening 58 is in registry with the openings 18 and 26 in the seat and gate, respectively, so as to allow molten plastic material to flow into the cavity 12.

' The spherical surface 56 corresponds in size and shape with the inner spherical surface 24 of the gate 20.

The nozzle 54 is provided with a fitting 60 which is secured to the nozzle 54. Suspended from the fitting 60 is a plate'62 which is attached to the fitting by means nozzle to register with the inner surface 24 of the gate 20 until the gate is rotated to the position shown in FIG.

2 where the surfaces 56 and 24 are firmly in contact with each other and the openings 58, 26 and 18 are in registry with each other. Note also that the springs 68 are in a compressed condition whereas the spring 44 is in an extended position. The end of the arm 40 rests against the plate 32 to prevent further counterclockwise movement of the gate 20.

As the nozzle 54 is withdrawn away from the mold, the spring 44 will rotate the gate 20 in a clockwise direction back to the position shown in FIG. 1. It should be noted that the left-hand end of the gate 20 contacts the lower edge of the plate 32 so as to provide a stop thereby preventing further clockwise movement of the gate 20 under the action of the spring 44.

Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications, apart from those shown or suggested herein, may be made within the spirit and scope of this invention.

What is claimed is:

1. A cut-off apparatus for a mold adapted to be opened and closed by the approach and withdrawal, re-

spectively, of the end of a supply nozzle comprising a mold cavity having an inlet, a gate receiving means mounted in said inlet, said gate receiving means having a semi-spherical seat opening outwardly away from said inlet, said gate receiving means having an opening in said spherical seat communicating with said mold, a gate having an outer semi-spherical surface adapted to bear against the semi-spherical surface of said seat and having an inner surface adapted to mate with said end of said supply nozzle, said gate also having a hole therein, means for rotating said gate in said semispherical seat, closure means connected to said gaterotating means for urging said gate into a closed position where said openings in said gate and said seat are out of registry with each other, means responsive to the movement of said nozzle towards said mold for rotating said gate against the action of said closure means and into an open position where said holes of said gate and said seat are in registry with each other and with said nozzle.

2. A cut-off apparatus as set forth in claim 1 wherein said gate-rotating means includes a pair of axially aligned rods connected to opposite sides of said gate and joumalled for rotation in said gate-receiving means, and an arm projecting outwardly from one of said rods.

3. A cut-off apparatus as set forth in claim 2 wherein said closure means includes a spring retainer means connected to said mold, and a spring connected between said arm and said spring retainer means.

4. A cut-off apparatus as set forth in claim 3 including a stop means for preventing rotation of said gate beyond a predetermined position when moving towards said closed position.

5. A cut-off apparatus for a mold adapted to be opened and closed by the approach and withdrawal, respectively, of the end of a supply nozzle,said supply nozzle having an opening and surrounding spherical surface at said endthereof, comprising a mold cavity having an inlet, a gate receiving means mounted in said inlet, said gate receiving means having a semi-spherical seat opening outwardly away from said inlet, said gate receiving means having a substantially'circular opening in said spherical seat communicating with said mold cavity, a semi-spherical gate rotatably mounted in said seat and having an outer semi-spherical surface adapted to bear against the semi-spherical surface of said seat and having an inner semi-spherical surface adapted to engage the semi-spherical surface of a supply nozzle, said gate also having an opening therein substantially of the same size as the opening in said seat, means for rotating said gate in said semi-spherical seat including a pair of axially aligned rods connected to said gate at the opposite sides thereof and joumalled in said gate receiving means, an arm projecting outwardly from one of said rods, a spring retainer means projecting outwardly from said gate receiving means, a spring connected between said spring retainer means and said arm for urging said gate into a closed position where said holes in said gate and said seat are out of registry with each other, an arm engaging means attached to said nozzle and movable therewith as said nozzle approaches said gate for pivoting said arm against the action of said spring and simultaneously rotating said gate into the open position where said holes of said gate and said seat are in registry with each other and with the opening in said nozzle.

t It I t t 

1. A cut-off apparatus for a mold adapted to be opened and closed by the approach and withdrawal, respectively, of the end of a supply nozzle comprising a mold cavity having an inlet, a gate receiving means mounted in said inlet, said gate receiving means having a semi-spherical seat opening outwardly away from said inlet, said gate receiving means having an opening in said spherical seat communicating with said mold, a gate having an outer semi-spherical surface adapted to bear against the semispherical surface of said seat and having an inner surface adapted to mate with said end of said supply nozzle, said gate also having a hole therein, means for rotating said gate in said semi-spherical seat, closure means connected to said gaterotating means for urging said gate into a closed position where said openings in said gate and said seat are out of registry with each other, means responsive to the movement of said nozzle towards said mold for rotating said gate against the action of said closure means and into an open position where said holes of said gate and said seat are in registry with each other and with said nozzle.
 2. A cut-off apparatus as set forth in claim 1 wherein said gate-rotating means includes a pair of axially aligned rods connected to opposite sides of said gate and journalled for rotation in said gate-receiving means, and an arm projecting outwardly from one of said rods.
 3. A cut-off apparatus as set forth in claim 2 wherein said closure means includes a spring retainer means connected to said mold, and a spring connected between said arm and said spring retainer means.
 4. A cut-off apparatus as set forth in claim 3 including a stop means for preventing rotation of said gate beyond a predetermined position when moving towards said closed position.
 5. A cut-off apparatus for a mold adapted to be opened and closed by the approach and withdrawal, respectively, of the end of a supply nozzle,said supply nozzle having an opening and surrounding spherical surface at said end thereof, comprising a mold cavity having an inlet, a gate receiving means mounted in said inlet, said gate receiving means having a semi-spherical seat opening outwardly away from said inlet, said gate receiving means having a substantially circular opening in said spherical seat communicating with said mold cavity, a semi-spherical gate rotatably mounted in said seat and having an outer semi-spherical surface adapted to bear against the semi-spherical surface of said seat and having an inner semi-spherical surface adapted to engage the semi-spherical surface of a supply nozzle, said gate also having an opening therein substantially of the same size as the opening in said seat, means for rotating said gate in said semi-spherical seat including a pair of axially aligned rods connected to said gate at the opposite sides thereof and journalled in said gate receiving means, an arm projecting outwardly from one of said rods, a spring retainer means projecting outwardly from said gate receiving means, a spring connected Between said spring retainer means and said arm for urging said gate into a closed position where said holes in said gate and said seat are out of registry with each other, an arm engaging means attached to said nozzle and movable therewith as said nozzle approaches said gate for pivoting said arm against the action of said spring and simultaneously rotating said gate into the open position where said holes of said gate and said seat are in registry with each other and with the opening in said nozzle. 